Introduction and selective removal of debilitating agent for permeability correction

Abstract

Abstract A debilitating agent is injected into a subterranean formation under conditions of time and injection rates such that it permeates both the more permeable zones and the less permeable zones. A flush is then injected under conditions of time and rate so as to selectively remove the debilitating agent from the more permeable zones. In one embodiment the debilitating agent is a polymerization inhibitor or poison. Then a material which will polymerize in the absence of the poison or inhibitor is injected. Since the poison or inhibitor will remain in the less permeable zones, little or no polymer is formed there. In the more permeable zones from which the poison has been flushed, polymerization occurs so that subsequently injected secondary or tertiary oil recovery fluids are diverted away from the thief zones to more effectively displace the oil from the less permeable zones. In another aspect of this embodiment, the debilitating agent is an inhibitor or poison for a reaction other than polymerization which forms a solid precipitate or other permeability-reducing plug. Alternatively, the debilitating agent is a depolymerization agent or a decomposition agent which will effect depolymerization of a polymer or decomposition of a chemical compound. The selective plugging then occurs as a result of the fact that the material causing breakdown of the injected polymer or chemical compound is absent in the more permeable zones as a result of the flush.

Inventors

• 👤 Hugh M. Barton, Jr.

Bibliographic Details